B4J Question ShowPDFinB4J / JFX8Printer - adding a print button

I'm trying to to add a print button to the pdfbox and JFX8Printer examples to print the whole pdf (loaded document) without much success, to start with I'm not sure how to call PDFRenderer in pdfbox , can someone help please?

The complete example is attached , printDocument is the added sub (together with JFX8Printer example)

Thanks in advance